000 AXNT20 KNHC 182130 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Dec 19 2023 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2130 UTC. ..SPECIAL FEATURES... Western Atlantic Gale Warning: A cold front extends from a complex low pressure system over the NE United States and enters the waters near 31N69W and extends SE to the southern Bahamas. A surface ridge extends from strong high pressure near 44N44W SW to near Puerto Rico. The pressure gradient between these features is supporting near- gale to gale force winds N of 26W within 120 nm east of the front. Seas are peaking near 18 ft over this area, with seas in excess of 12 ft covering the waters N of 25N between 60W and 75W. The surface low will continue to move rapidly NE and further from the area tonight. This will loosen the pressure gradient over the discussion waters, and diminish winds below gale force late tonight. Central Atlantic Gale Warning: The pressure gradient between a strong 1047 mb high centered near 44N44W and a 1011 mb low pressure center near 23N47W is supporting an area of near- gale to gale force winds N of 25N between 42W and 55W. Seas over this area are peaking near 19 ft. Seas greater than 12 ft cover the waters N of 22N between 40W and 60W. The low will move westward, while the high center moves eastward over the next couple of days. This will loosen the pressure gradient, and diminish winds below gale force by the middle of the week. Please read the latest NWS High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details on both Gale Warnings. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 06N09W to 04N15W. The ITCZ continues westward from 04N15W to 05N35W to 03N43W to 05N49W. Scattered to numerous moderate convection is noted from 01N to 09N between 16W and 35W. ...GULF OF MEXICO... A surface trough extends southwestward from central Florida to the central Gulf. Moderate to fresh NNW winds and seas of 5-7 ft prevail E of 90W. Gentle to moderate winds, and seas of 3-5 ft are over the Gulf waters W of 90W. For the forecast, high pressure will dominate the weather pattern across the Gulf waters through Tue, then strengthen N of the region Wed through Thu to produce fresh to strong NE to E winds across the eastern Gulf, including the Straits of Florida. ...CARIBBEAN SEA... A stationary front extends from the Windward Passage to the SW Caribbean. Fresh to locally strong winds are W of the front, with seas of 6-8 ft. Gentle to moderate winds are east of the front, with seas in the 4-6 ft range. For the forecast, the front will remain nearly stationary on Tue and dissipate on Wed. Fresh to strong northerly winds and seas to 9 ft are expected in the wake of the front through Wed. High pressure will build SE across the western Atlantic Wed night through Fri to produce fresh to strong NE winds in the lee of Cuba and the Windward Passage. At the same time, fresh to locally strong trades are expected in the south-central Caribbean, including the Gulf of Venezuela, mainly at night. ...ATLANTIC OCEAN... Please read the Special Features section for more on the ongoing Gale Warnings. Aside from the area of gale force winds, fresh to near gale force winds are N of 20N between 40W and 70W. Moderate winds are W of 70W, moderate to fresh winds are E of 40W, and gentle to moderate winds are elsewhere. Aside from the area of 12 ft seas, seas greater than 8 ft cover the waters N of 18N and W of 35W. Seas of 7-9 ft are N of 20N and E of 35W. Elsewhere, seas of 5-7 ft prevail. For the forecast W of 55W, gales ahead of the front will persist through tonight. The front is forecast to reach from 31N69W to Haiti Tue morning, and from near Bermuda to the N coast of Hispaniola near 20N70W by Wed morning. Strong high pressure will build into the western Atlantic behind the front Tue night through early Thu to produce fresh to strong winds. $$ AL